From: veck@pshrink.chi.il.us (Chelloveck) Gyruss Pinouts These are from the manual for my upright. I'm reasonably sure that they don't match the actual pinouts on my board. For instance, my board is stereo but all through the manual (including these pinouts) it's indicated to be monaural. Parts Side | Solder Side --------------|-------------- +12V | 1 | A | -5V Speaker | 2 | B | Speaker | 3 | C | 2P Speed ("Speed" is actually "Fire"?) 2P Right | 4 | D | 2P Left 2P Start | 5 | E | 1P Start 2P Up | 6 | F | | 7 | H | 1P Speed 1P Left | 8 | J | 1P Right 2P Down | 9 | K | 1P Up | 10 | L | Coin | 11 | M | 1P Down | 12 | N | Blue | 13 | P | Green Sync | 14 | R | Red | 15 | S | GND | 16 | T | GND GND | 17 | U | GND +5V | 18 | V | +5V It seems your Gyruss pinout for an upright machine is incorrect, you are missing the second speaker pins located on A15 and B15. I am pretty sure the one you have is correct however for the cocktail version. GYRUSS CKT SIDE PARTS SIDE ----- ----- A1 -5V B1 +12V A2 SP 1 B2 SP 1 A3 PL 2 SHOOT 1 B3 PL 2 SHOOT 2 A4 PL 2 LEFT B4 PL 2 RIGHT A5 1 PLAY START B5 2 PLAY START A6 PL 1 SHOOT 2 B6 PL 2 UP A7 PL 1 SHOOT 1 B7 SVC A8 PL 1 RIGHT B8 PL 1 LEFT A9 PL 1 UP B9 PL 2 DOWN A10 COIN 1 B10 COIN 2 A11 PL 1 DOWN B11 COIN CTR A12 B12 A13 VID GN B13 VID BL A14 VID RED B14 SYNC A15 SP 2 B15 SP 2 A16 GND B16 GND A17 GND B17 GND A18 +5V B18 +5V